As an additive manufacturing technology based on a powder spreading method, SLM (selective laser melting) technology is a technology that metal powder is completely melted under a thermal action of a laser beam and molded by cooling and solidification. The technology can transform a design idea into a physical model with certain functions quickly, directly and accurately. Compared with traditional processing methods, the SLM can shorten a product design and manufacturing cycle, promote competitiveness of enterprises, enhance profitability of enterprises, and establish a brand-new product development mode for industrial product designers and developers.
A powder spreading apparatus of an existing SLM device mainly consists of a powder feeding chamber, a recycling chamber, a scraper and a bracket. The specific process is: spreading, by the scraper, a layer of powder material on an upper surface of a formed part; scanning, by a beam, a cross-sectional contour of the layer; sintering the layer, and bonding the sintered layer with the formed portion below. When the sintering of one layer is completed, a workbench is lowered by a thickness of one layer, and then the scraper spreads a layer of powder again to perform sintering of a new layer of section until the entire model is completed.
When a part is processed using an SLM device, precision of powder spreading by a powder spreading apparatus directly affects the forming quality of the part. If a surface is uneven at the time of powder spreading, the corresponding area of the part will form projection and depression. Adding layer upon layer, It is most likely to cause a damage to the part. Even if the processing is completed, there will also exit problems such as low precision. Most of the existing SLM devices are incapable of testing the performance of powder spreading, and as a result, it is difficult to ensure the precision of powder spreading which will affect the forming quality of the part.